N/A'ing my Turbo; LS1 conversion project

[PorscheNut924]

That sounds so goooood.

I finally found a 944 Turbo for cheap, which will donate its engine to my 924S. Hopefully sometime within the few years I can pack an LS1 engine into the 944 Turbo shell and end up with two very fast cars.

[Lapkritis]

Very nice. Those are healthy numbers too.

[beamishnz]

Just read this thread from beginning to end. Great read! Really impressive project, looks like you've given it heaps of thought, researched it well and are now enjoying the results!

The only thing that frustrates me is that the shop that you judged to be good, did not live up to your expectations. That happens to me so often when I try and save time by delegating work out ... I find that so frustrating!

Look forward to hearing further updates as you shake out the last of the gremlins

[Techno Duck]

A little update..

Have not been able to drive the car much since i had it tuned due to work / travel.

Still having issues with the shifting also. I have narrowed it down to the torque tube spinning continuously even with the clutch pedal depressed. I have ruled out not enough throwout bearing travel as being the issue, have ran with and without the throwout bearing shim provided by Spec. Despite all of the travel, the clutch disc is dragging on the pressure plate.

Going to tear it down again for inspection, ive got a few ideas as to the cause...

-Possible bent clutch disc; could have been caused while installing the engine, shipping damage or just manufacture defect
-Inspect splines on torque tube; could be hanging up on the splines, i dont think this is it because the disc and be wiggled back and fourth with clutch depressed pretty easily.
-Inspect pilot bearing and adapter; Possible the bearing or adapter is in contact with the clutch disc, i also feel this is unlikely because all of this was double checked before.

A few other things to complete also; going to remake all of the oil lines which i hope will stop the sweating fittings on the oil cooler. Decided to redo all of the lines with Aeroquip hose and fittings.

[Techno Duck]

Monthly update;

We finally figured out what was causing the shifting issues a few days ago. After tearing down the clutch assembly, we found the pilot bearing and adapter had started walking out of the crank. This was causing the adapter / pilot bearing to press up against the clutch disc hub, which in turn was causing it to drag on the pressure plate.

Loctite bearing retaining compound was used on the adapter so it should stay put this time around.

Below you can see where the pilot bearing / adapter was rubbing on the hub. We replaced the disc with a new stage 2 from Spec for good measure.



We also checked the engagement of the torque tube into the pilot bearing for good measure. Here it is mocked up with no pressure plate, flywheel or clutch disc.



Ive put just over 100 miles on it so far and it now shifts without any issues finally. Being able to drive it now without the shifting problems i can say it is a true pleasure to drive. Despite all the issues that popped up during the build i can say it was really worth all the work and money spent.

Now that i can focus on some small odds and ends, i finally hooked up the check engine light. Originally i had this tied into the 'low oil level' light on the cluster. But i found the circuit for the low level light is fairly complicated and involves a timer..as a result it would give me some weird occurrences of the light being illuminated due to how the light operates. Read the owners manual for a description and you will see what i mean! I used a 12v panel mount LED and cut a sheet of aluminum to fit into one of the blank spaces on the gauge panel below the radio. All that needed to be hooked up were a 12v to the LED and the ground wire to the engine harness CEL ground wire. As ive said before, the wiring on this engine swap was one of the most simple parts.



Another thing i am working on is improving the cooling at idle / low speeds. Right now i am using a single 16" SPAL puller fan. The fan is barely adequate; it will maintain temperature when it kicks on but is not able to actually cool the car off. So after extended idling the fan will stay until you get moving again. I feel the lack of a proper shroud around the fan is the cause of this. My other gripe with this fan is it pulls quite a few amps at startup. The fan is rated at 19.5amps while running, at start its probably closer to 25amps+. I purchased a set of dual SPAL 11" fans with shroud that should work with some modifications. These two fans will flow an extra 700cfm about and also utilize a shroud which should provide a big improvement over what i am using now. Each smaller fan is rated at 11amps running, my plan is to use the PCM to stagger the temp each fan kicks on at by 1 degree so they dont both kick on at the same time. This will reduce the instantaneous current draw. Ill report back in a week or two once i get everything figured out.



Hoping to make a track day the first track day in late August.

[Techno Duck]

Ive got just over 2500 miles on the swap and next month it will be one year since completion. So here is the one year update...

The car has been running great. I did a two day track event in October, car ran great but my second day was cut short by a leaking power steering rack. The original steel hard lines were bent to fit around the oil pan which weakened the banjo fittings. I put in a rebuilt rack and converted all of the hard lines to -4AN stainless braided hose so i could route everything away from the pan.



The cooling issues have been solved by putting a stronger 16" fan in with straight, rather than curved blades. The straight blade fans are louder, but are able to pull more air through a thick radiator core like what i have on the car now.





Ive also relocated the heater control valve to a more friendly spot. Originally the valve was mounted right over the headers and it was actually starting to melt from the heat! I relocated it to forward of the headers and remade the heater hoses to fit a little better. Fits like a glove!



The car performed great on the first track day, the handling really hasn't changed much at all. Still very predictable and balanced. The only major difference is i am now very careful to have the wheel almost straight before really getting on the gas at corner exit. The engine makes 380whp / 360tq so its not a super powerhouse, but definitely will step out if your not careful. With the turbo you could be practically full throttle mid turn and by the time you unwind the wheel full boost is just coming on. The hydroboost brakes worked great but have taken some getting used too. The pedal is very sensitive now to input. Previously, 0-100% brake was achieved through say 2-3 inches of pedal travel. Now with the hydroboost, its changed to maybe 1-2 inches of travel. Overall though the car felt great and by the end of the first day i was pretty comfortable with it.. just like old times!

No issues with cooling; though i think i may need to size up the oil cooler eventually. I was running around 230*F at the end of the session in about 50 degree ambient temps. This might be problematic during those 90 degree track days. Ill keep an eye on this over the course of the year. I had originally sized this oil cooler to fit under the nose panel but ended up placing it in front of the radiator. So i can definitely go quite a bit larger.

So the first year as i expected i was working out all of the bugs. This project was no small undertaking but the end result i think was well worth it. I am pretty confident the car is pretty well shaken down at this point. Looking forward to more track miles next year!

[Lapkritis]

Nice read. Glad you're enjoying it.

[pontifex4]

What an awesome build.

I have the opposite braking problem with a swapped (non-944) race car right now: the assist is fine, but the master cylinder is a little small for the very big brakes so there's too much pedal travel. I wonder if there's a different master cylinder you could fit, or if you could reduce the brake boost a little to change the pedal feel.

[Techno Duck]

Charlie, while mocking up everything for the brakes the push rod on the hydroboost unit is moving to almost full stroke so i dont think there is much i can do. The entire brake setup (hydroboost and master cylinder) is from a '00ish Ford Mustang so I am guessing it must have a slightly longer pedal which increases the pedal travel somewhat. Its really not too big a deal, just takes some getting used to. I think eventually i would consider putting in a Tilton pedal box

Depending what kind of setup your using, you can find a master cylinder with a larger bore size. This will lower your pedal travel, but the downside is that it will increase pedal effort. That is mostly an issue though if you are running a manual brake setup. I tried 4 or 5 different size clutch master cylinders for my car before i felt i had the best one, its surprising how much +/- .05" in bore size makes in pedal effort and the engagement point of the clutch.

[Techno Duck]

Unfortunately i haven't been able to drive the car much after reloacting to SoCal. The car is currently in NY; in storage at a friends shop. I was back in NY a few weeks ago and was able to put about 500 miles on the car. Currently at just over 3k miles since the swap.

Many bugs had to be worked out in that time but its running great. I did a 2-day auto-x also and had a ton of fun with the car. The 944 chassis is really well suited to the power band of the LS. Its still surprising also how quickly the car changes directions with the big lump of a V8 upfront. I know the weight different is marginal between the two but still surprises me! This was the first test of the new steering rack setup and it held up great. Right now the car really doesnt need much more attention which is a relief, i think all the bugs have been worked out by now.

Ive been kicking around the possibility of selling the car. Registering the car in CA will be extremely difficult as i never thought i would have to pass a smog check when it was being built. So that means it will likely turn into a trailer queen to and from the track. I bought a 911 3.2 earlier this year also so restomodding that has become my new focus. Still unsure what to do but i am looking into storing it for a couple of years until i decide to go tow vehicle + trailer.

Here are some recent pictures

[Lapkritis]

I've done the long term storage thing before for a couple years with a car... And also the SoCal thing too. Just a career hop that brought you to SoCal or something more lifestyle/long term choice? There is an option of a rural Arizona (not maricopa county) address or just flying New York tags indefinitely. I ran out of state tags the years I was there and have a friend who still runs Maine tags now nearly decade later. Not sure if NY ties registration to an inspection.

[Techno Duck]

Got tired of NY and needed a change of pace; hard to beat the weather also!

I think i have thought of every possible scenario to keep the car registered. NY does tie the registration to the inspection so best case scenario ill be okay for 2-years until my registration expires. I did eventually plan on towing to and from the track, just not ready for that type of commitment yet. The other catch is storage, hate to be paying for monthly storage but at the same time i love the car and know that its one that could never be replaced. I cant even estimate how much time and money i have into this car over the past 7-8 years.

[Techno Duck]

The car now resides in SoCal, had it retuned for 91oct this morning. Took out 2 degrees of timing up top to increase the safety margin, result was a drop in 20bhp. Still puts down 363whp / 349ft-lbs which is more than enough

I don't drive the car much on the street anymore but when i do its always fun...for about two hours max then the loud exhaust, heavy clutch and terrible drone at 2500rpm gets to me. Getting the car ready to hit some tracks on the west coast next year, retuning for 91oct pump gas was high on the list. Pretty much the last thing to do is quiet the car down a bit and install a 2nd muffler so it will pass sound at Laguna Seca. Just over 3.5k miles on the swap with a few track and auto-x days on it. So far so good. One thing to address is the shifting which has very high effort right now. Not sure if its linkage related or possibly the fluid (perhaps to slippery for the synchros). Not sure what the shop used when they put my transmission in.

https://youtu.be/uaeCsMWr4Tk

[jcommin]

Nice to hear from you Jon, Happy Holidays to you.

[running_cold924]

Still looking good Jon, enjoy the weather out there (for all us east coasters back here)

Still very healthy numbers after the re-tune....and enjoy the 911, last of the air-cooleds.

[Techno Duck]

Well as far as projects go i think this one is done, so i figure its a good time to move on. 13 year 944 owner, 8 years with this one.. hard to believe!

1988 944 Turbo
Guards Red / Black Interior
132,XXX miles
4k+ miles since V8 swap

Details available here;
FS: LS1 swapped '88 944 Turbo

[running_cold924]

Man, say it ain't so!! Been in the game almost as long as you, watched the build on the turbo motor grow then got pulled for the v8. Been a pleasure reading this thread for the last couple years. Who ever buys this car will have quite the beast and correctly built as well. Looks good Jon, as always. Good luck with sale!

[Alexb944]

Did you use the porsche crossmember? or fab one for the Ls? also did you use the original brembo brake calipers or did you need to upgrade the caps and rotors? lastly atm did you need to reinforce the chasis or anything like that? im contimplating this swap myself and any info i could get would be awesome.

[Techno Duck]

Originally Posted by Alexb944

Did you use the porsche crossmember? or fab one for the Ls? also did you use the original brembo brake calipers or did you need to upgrade the caps and rotors? lastly atm did you need to reinforce the chasis or anything like that? im contimplating this swap myself and any info i could get would be awesome.

The original crossmember is used but it is mounted with 1/2" spacers to give you more clearance under the hood, mainly around the throttle body.

I am still using the Brembo calipers, though i have 928S4 (same as 944 Turbo S) calipers on the front. I had done this prior to the engine swap. With the right pads and some form of cooling i have found this setup to be more than adequate on the track.

No other changes to the chassis are required, the 944 chassis is solid to begin with and it handles the LS without any issues. My engine isnt making crazy power levels either, guesstimating with my initial tune of 380whp it is probably in the area of 440bhp at the crank. There are more than a few well equipped 944T's making similar power levels. The big difference being in power band though, the LS is making close to 200ft-lbs of torque as soon as your done engaging the clutch . Just need to be easy on the drivetrain, no hole shots or launching the car, always roll on the throttle.

Save yourself time and money and just buy mine

Originally Posted by running_cold924

Man, say it ain't so!! Been in the game almost as long as you, watched the build on the turbo motor grow then got pulled for the v8. Been a pleasure reading this thread for the last couple years. Who ever buys this car will have quite the beast and correctly built as well. Looks good Jon, as always. Good luck with sale!

Thanks man, my time with this car was an experience none the less! To say i am a 944 enthusiast is probably a huge understatement. I bought an air cooled car last year and have been restomodding it which has sucked up all my time and money. I have my eyes set on another, i picked an expensive time to like air cooled cars .

[souleater]

meanwhile back to the thread. Im listening to you Duck.